The Remains of the Night
by TheBadWolfDoctor
Summary: Princess Luna has turned from her thousand years of banishment, and Celestia is overjoyed! Finally, she can mend her relationship with her sister. And there's absolutely no possibility that Nightmare Moon has survived, lurking in the depths of Luna's psyche, is there?


The sound of something _expensive_ hitting the floor – probably, Celestia guessed from the distinctive hollow _whine_ that rung out, though she dearly hoped not, one of the few early Caballus-era pieces that had managed to survive the war intact – forced the princess' eyes open. The noise seemed to echo throughout the entire palace, but Celestia was quite well aware of the fact that it was merely her semi-somnambulant state playing tricks on her perceptions. For a moment, she flirts with an idea; she allows it a few brief seconds of life, giving it free reign to tease her playfully, though it quickly turns mocking.

 _Ignoring it was never going to an option, was it_?

Princess Celestia was cursed; she was one of _those_ ponies that you'd often heard about, but couldn't believe actually existed: one who, when roused, actually got up out of bed and went about their day. The promise of a long life had not dulled her desire to seize every hour of every day, and lately, there had been more reason than normal to get an early start.

 _A reason_ , she thought ruefully, _not unconnected with the priceless object that had just been destroyed_.

Her commitment to this noble ideal takes a bit of a battering when the cold air assaults her body; goosebumps rose across her flesh in response to her telekinetically hurling her covers across the room, and she briefly wondered what the point of all that cream-coloured hair adorning her was. Hesitating for only a second longer, she finally dragged her large, elegant form off of the bed and stood in front of the gilt-edged golden mirror that dominated the marble wall.

Yes, the décor was a bit ostentatious and not really her thing, but _you_ try telling a royal architect that you wanted something simple and unshowy.

Celestia's bed could easily hold two or three alicorn-sized ponies, and as she quickly went about her ablutions in the en-suite, she entertained herself by imagining the scandalous headlines that would no doubt be printed should the press ever get wind of something of that nature ever happening. Though she was more than a thousand-years-old – probably _much_ more, but she'd long since given up counting and the date of her birthday celebration no longer bore any relation to her actual date of birth – she had the body of a pony in their physical prime, and even without the added draw that came with being royalty, there were doubtless many in Equestria who would happily court her.

 _If nothing else, it would liven up an otherwise dull period for the news_.

Shaking her head to free herself from these distracting thoughts was difficult, and all she really succeeded in doing was soaking the carpet as her flowing mane sought to dispense with all the water she had been using to try and straighten it out.

What she'd really been trying to do was ignore the fact that, ever since she'd woken up, further noises had been tumbling out of the suite a few doors down.

A suite that, until very recently – since yesterday, in point of fact – had gone unoccupied for more than a thousand years.

 _This was inevitable, I suppose, but had I really expected it to be this bad_? _Did I have any expectations at all_?

To say the least, her first day back had been … trying. Information _and_ sensory overload did not a happy pony make, and there had been so many unfamiliar things for her to try and make sense of far too quickly. _Tartarus, even the_ castle _itself was new to her. We'd still been in the old place in the Everfree when … well, just when_. Celestia wanted to give her space and time to adjust, but she didn't know when – or even _if_ – she should try and talk to her. She'd been locked in her room, apparently alone, for almost thirty-two hours now.

Celestia let loose a sigh; a sigh that, should anypony have been around to hear it, would have sank their spirits far more deeply than anything else imaginable. She knew that her little ponies looked to her to have all of the answers, no matter how bleak things might've looked, but now she was torn. When it came to Equestria and her subjects, she was a stoic leader; when it came to her family, and matters of her own heart, she was as fragile and as vulnerable as anypony else. She secretly resented this weakness, but she also knew that it was important.

It helped to keep her grounded.

 _How do I bridge this gap between us, sister_? _I've waited patiently for a millennium to have you back, and I will not let you go again, but … how do I do that_? _How do I keep you this time_?

The half-smile that Celestia had allowed herself in the moment of relative calm soon withered as yet another object collided with the wall. Had Twilight Sparkle been here, she probably would have started reciting verbatim her psychology textbooks and what they said about sibling interaction, particularly after a long period of separation or … after a fight. Even now, the thought briefly crossed her mind of summoning Twilight for assistance, but it wouldn't be fair to drag her from her new friends and her new life in Ponyville to listen to a domestic dispute.

Mind you, it was a domestic dispute with a thousand years of pain behind it. In the end, Celestia decided against it; she was undeniably brilliant, Twilight, but she was also inexperienced and nervy, and a cool head was required for this particular situation.

 _Still, she was the closest thing I had to an equal for so long. And one day, Goddess-willing, she will surpass me_.

Upon exiting her room – after one last quick check to make sure she radiated that bizarre mixture of approachability and detachment that she aimed for each day, wanting her subjects to find her open but not so much that they came to her with every little problem they could easily deal with on their own – Celestia found two guards on either side of the doorway and she bid them a strained good morning. It was clear from the tightness in their faces that they had also borne aural witness to the uproar from a few doors down, and were equally unsure as to what, if anything, they were supposed to do about it, but still they responded with calm salutes.

Undoubtedly, they had been waiting for Celestia to come and sort it out herself. Already, in fact, they seemed to be lightening up a bit, sure that the princess could deal with _anything_. Even her own unruly sister.

"When one of the palace staff went to check on her earlier, she said she wanted to be left alone," one of the guards said. "We don't know whether, er, you were included in that restriction or not."

A thousand years of division summed up by one simple oak door; Celestia stood, more reticent than she'd ever been about anything, with a golden-shod hoof poised in the air like a judge about to bang their gavel and deliver a sentence. She tried to tell herself that Luna had just been blowing off steam – after such a long period _away_ it was only natural that she would have some stress to deal with – and that she was worrying over nothing, but a prolonged stream of invective aimed at seemingly nothing in particular convinced her otherwise. If this was Luna's way of coping, then her sister dearly needed to learn the simple pleasures of a soapy bubble bath and a team of masseurs immediately. Luna's voice, from what she could make out, was angry … angry, but there was a not of something else in there, too.

 _Fear_?

Politely, though _timidly_ might've been a more apt phrase, Celestia's hoof pecked at the door like a startled colt fumbling over his first kiss. So tiny, so delicate was the knock, even Celestia herself was having trouble hearing it. Almost immediately, however, all activity from Luna's chamber ceased, and though she knew that she ought to be grateful for the cessation in whatever hostilities she was enacting against the irreplaceable décor, Celestia was even more alarmed by the protracted, awful silence. The sort of silence that one could almost hear as an accusation.

The absolute stillness preyed on her mind, and she was tempted to simply turn tail and leave, letting Luna get on with whatever it was she was doing, but … what was that?

A single, solitary cry. The sort of half-hearted sob that one can only manage when they know that no one is really listening to them, anyway.

 _To Tartarus with royal decorum_! Not even bothering to use her magic to incinerate the door, or teleport through it, Celestia's first instinct was to shoulder barge the heavy wooden barricade between her and her sister. It splintered into a million fragments under the assault, and Celestia winced as shards dug into her skin. Very few things in Equestria could stand up to the strength of an alicorn – that perfect blending of all the pony races – especially not one empowered by love and compassion for one's own kin.

Celestia had lived for a long time; so long now that even she had trouble remembering how it had all began, and it would doubtless – barring accidents – continue for a long time to come. Few things in life had the force to startle her, to shake her to her very core. She had experienced almost everything that a pony was capable of and had come through it stronger and wiser.

But the sight she was confronted with now made her grateful that she'd not had any breakfast yet; still, her stomach was content to bunch itself up into knots, and a cold shiver ran up her spine as sweat formed on her brow. She took two steps into Luna's chambers with all the confidence of somepony wanting to take eighty steps in the opposite direction.

Truly, Celestia thought, the castle architects had done an exemplary job in matching Luna's new suite to the exact specifications – though they hadn't understood the necessity, as they'd never believed that she was coming back – of her old one in the Everfree Forest; right down to the wrought-iron fixtures and fittings around the overstorey, through which one could have an almost-panoramic view of Equestria in all of its glory, every detail was perfect.

Had been perfect, anyway.

The room looked as though it had just played to the world's most raucous party; Discord might've appreciated it, if the old meddler ever got out of his stone prison, but Celestia's purple eyes could only focus on one thing amidst all the debris and detritus. A tiny, fragile purple thing that could not have – yet somehow had – caused all of this chaos, delicate, feathery wings wrapped around herself like a protective sheath.

Luna had put those hoof-deep holes in the reinforced marble walls.

Luna had smashed all of those one-of-a-kind pots and vases.

Luna had torn those first-edition hardbacks apart, pages fluttering upending across the floor like lifeblood disgorging from a wound.

Amazingly, going by the cursory examination that she was able to perform from this angle, Celestia found that Luna herself appeared to be unharmed. No broken bones, no cuts, not even a feather out of place on her exquisite wings.

So intent was she on her snivelling little sister – so childlike, innocent and helpless, snot and tears sticking to her face as she wept with abandon – it took Celestia a moment to realise something that horrified her still further: upon leaning down to get a better look at Luna, some of the hoof-prints in the wall resolved themselves into something that looked almost like … _words_.

As a matter of fact, painstakingly, and no doubt _painfully_ , etched into the alabaster designed to withstand an invading army was an entire sentence. It took Celestia a couple of minutes to fully wrap her head around it and, when she finally made sense of the words, she felt sick.

YOU ARE MINE, NOW AND FOREVER, ELATHA.

Celestia took a deep breath, trying to quiet the raging inferno boiling within her; in the whole span of Equestrian history, only five ponies had known that _Celestia_ and _Luna_ were merely titles afforded to the princesses. Epithets to describe what they did – mastery over the Sun and Moon respectively – rather than identify who they were.

Two of them were Celestia and Luna themselves.

Two of them had long since passed on to the next realm, may the Goddess grant their souls eternal peace.

And the last one was …

… the _fifth_.

Nightmare Moon.

Celestia watched rapt as Luna's wings quivered, trembling uneasily as agitation consumed her, and she got her first proper look at her sister's face; pale, waxy and miserable. It was a far cry from the strong, confident – brash, even – young pony who had once stood by her side through so much. Before Nightmare Moon.

Words came tumbling out of Celestia's mouth without much thought in response to Luna's wretched, despairing countenance; they were meant to be reassuring, comforting, but all they did was admit to the fact that even the ruler of Equestria was feeling jittery, too. She took in the carnage surrounding her once more, wishing desperately – even going so far as to be childishly annoyed that there _wasn't_ – that there was a simple spell that would fix everything.

 _Was I foolish to think that we'd be free of this millennium-long nightmare so easily_? _The Elements of Harmony should have obliterated Nightmare Moon, remove all traces of her dark psyche from Luna's mind. What went wrong_? Involuntarily, Celestia shuddered; she had no particular desire to relive those terrible days, especially the many evil acts Nightmare Moon was able to carry out by using Luna as her instrument.

 _Or is that just me being naïve_? _Trying to let her off the hook so that she can reintegrate back into pony society because I want it more than anything_? _Am I turning a blind eye to the question I want to ask, but never can_?

 _How much of it was you, Luna_?

Jealousy had played its part, of course; nothing stands in the shadow of something that burns so brightly without feeling a twinge of envy, and thousands of years of covetousness plus an inferiority complex borne out of a seeming disregard for everything that she had done for Equestria was a perfect recipe for psychosis. But that poisonous influence, that demonic entity that had so skilfully manipulated her … had it been responsible for pushing her over the edge of madness?

 _Would you have eventually rejected me, even without Nightmare Moon's help_?

It was easy, oh, so easy, for Celestia to believe that her dear, sweet sister was simply the innocent victim in all of this. Just a pawn of a higher power.

 _Because if I were to believe otherwise, I might stop loving you_.

Luna's eyes opened so suddenly that Celestia took a startled step back; she blinked a couple of times, as if trying to comprehend why her older sister was standing there, towering above her just as she had done all those years ago. "Celestia?" she asked in a low, shaky murmur. The voice of a child faced with something that they do not yet understand, but recognise as being important. The voice of a child looking to an elder for aid. The voice of a child about to learn the hard way that adults don't always have answers for them. "What … what happened here?" Her tone turned fearful as she fully absorbed the destruction and the message embedded in the wall. "Did I do this?"

For the first time in years, it occurs to Celestia that Luna was still – in alicorn terms, anyway – basically a child when she had been exiled. _When I was forced to exile her_. "What do you remember?" Celestia asked quietly, trying to keep some kind of grip on the situation. Luna needed her, now more than ever, and she could not let her fears tear her apart. "From last night, what's the last thing that you remember?"

"Ah, um," Luna said, pulling herself to her hooves and shaking her head to try and clear it, "the homecoming. I was exhausted and bewildered after the celebration and I returned to my chambers in order to meditate. When I awoke-" she punctuated her words with a sweeping gesture of what remained of her suite "-it was to all of this. It's back, isn't it? The Elements-"

"-For whatever reason, yes, it would seem that the Elements of Harmony were unsuccessful in fully purging Nightmare Moon's presence from your mind," replied Celestia, maintaining a steady tone of voice despite the growing anxiety building up within her. Luna needed support, something to act as a barrier between her and the insanity, and Celestia was determined to be it.

"I knew it." Luna spoke so softly that Celestia almost didn't hear her words; they weren't pitiful or angry, merely … resigned. She allowed her head to slump forward, a defeated expression colouring her muzzle, and her breathing became laboured. Her wings spread out of their own accord, reacting in a fight-or-flight response, only there was nowhere that she could run to to escape this particular threat. And possibly, no way to fight it either. "I wanted to believe, so much I wanted to believe it, sister, that the nightmare was over. It was never meant to be."

Celestia did the only thing that she could do; extending her wings to their full length, she encircled the smaller pony with them and pulled her in close. "Why do you say that?"

No doubt, the rapid heartbeat of her older sister betrayed the fact that she was just as tense and nervous as she was, but Luna did not mention this; in a way, it comforted her to know that Celestia was just as much flesh and blood as other ponies were. She wasn't some all-powerful Goddess, just … her sister. And that was more important. "I was never meant to have the time I wanted, to make amends to Equestria, to apologise for every hateful thing I ever did to you while … while under her influence." Floods of tears came unbidden, soaking Celestia's coat.

Unconsciously using the same cooing voice that had once brought them so much comfort as fillies, Celestia whispered into Luna's ear, "Sh, sh. It's okay. We'll figure this out." She brushed her sister's flowing mane softly just as her mother had once done so long ago, hoping that it would have a similar effect in calming her down. From the slump of her withers and the peaceful smile that crossed her face, Celestia guessed that it was working. She even started to hum an old half-forgotten lullaby that soon brought their heartbeats down to something like their normal rhythm. "Feeling better?"

Looking up at her sister, blue eyes filled with unconditional love and absolute faith, Luna managed to say, "A little bit, thank you."

Celestia barely heard her, however; for just a moment, she wasn't seeing her younger sister, but somepony else entirely. Another pony who had once looked at her with those same eyes, that same expression: inquisitive, bright, _expectant_. A pony who trusted her implicitly, and wanted her to have all of the answers, no matter how insurmountable a problem might've seemed.

"Is there anything that we can do to stop it, Celestia?" Luna asked. She frowned, wriggling in the grasp of her sister's wings. "Surely, there must be a way?"

With the very soul of Luna at stake, Celestia hated more than ever breaking that unshakeable faith all of her little ponies had for her; she did not have an answer, however, only a few stray thoughts that didn't seem to lead anywhere in particular. "If there is, then I do not know what it is," she said, holding her sister closer. "I knew that there was a small chance that some part of the Nightmare parasite might survive the Elements of Harmony, but there was no way to be certain until they'd actually done their work." She looked directly into Luna's eyes, hoping that she would understand. "Unless we find a way to destroy it completely or otherwise nullify its effects, it will continue to grow in strength until-"

"-Until it consumes me once more and I am nothing more than a slave to its will?"

"Yes."

Luna straightened up, disentangling herself from Celestia's embrace. "Then, there remains but one option that is open to us, dear sister."

Celestia opened her mouth in puzzlement before it dawned on her to what her sister was referring. "No, I will not go down that road ever again. Losing you once was enough." _How casually you make this suggestion. Do you realise what I've gone through, sister_? _Do you know what an empty abyss my days were without you by my side_?

Hardening her tone, Luna said, "I have no desire to become that monstrosity again. I have no desire to see Equestria torn apart again." More softly, she went on, not quite able to make her gaze, "Celestia, I have no desire to hurt you again."

"It doesn't have to be this way. It may not even happen," Celestia replied weakly, knowing that Luna did, in fact, have a point. Wasn't it better to stop it now rather than wait until Nightmare Moon had more power, had gained more of a foothold in Luna's still-frail mind?

"It is already happening," Luna said, gesturing to the ruined suite again. "For now, it seems, she, it, can only manifest herself when I am asleep, when I am not in control, but that won't always be the case. She's patient and cunning, and once she has the power to, she will kill you and turn Equestria into a realm of endless night."

"Luna, I will not banish you to the Moon again." Celestia realised that she was getting irate and forced herself to modulate her tone. "Even when the Nightmare entity had full control over you, I didn't want to do it, and it was absolutely the worst thing I've ever had to do in my life when I finally used the Elements to defeat … _her_. There's still hope, still a chance that things will turn out differently the second time, now that we know more about it."

"I'm not strong enough to contain her," Luna said pathetically, tears forming in her eyes once more.

"Yes, you are. You're my sister and you will have my meagre strength in addition to your own. We will find another solution."

"There isn't one," replied Luna. "Celestia, dear sister, look at me, please."

Doing so only reluctantly, fearing that her resolve might shatter, Celestia did not see the one-time Princess of the Night, nor did she see a powerful alicorn in her own right, all she saw was one of her little ponies – her own baby sister – who needed a helping hoof to solve a problem.

"Nightmare Moon must not be allowed to walk this earth again," Luna said sternly. Looking down at the floor, she continued, "Obviously, this is not what I wanted to happen. To be exiled a mere day after returning is rather absurd, but the greater good of Equestria must be served. I have had a taste of freedom and-" more tears "-I was able to see you one last time. Who knows? In another thousand years or so you may be able to destroy Nightmare Moon for good with the Elements of Harmony."

"Can't we just ask her nicely to leave you alone?" Celestia asked, trying – badly – to lighten the darkening mood hanging over them. "One day … just isn't enough. There's so much I need to say to you, so much for you still to see." _I had never thought the Goddess cruel before, even when she took our parents away before their time, but this smacks of a sick practical joke. Have I done something wrong_? _Was I a poor leader and this is my divine punishment_? _What did I do that was so terrible that I must be castigated in such a fashion_? On the verge of breaking down, Celestia said, "There _must_ be something that we haven't thought of."

Thoughtfully, Luna said, "Maybe … maybe you had the answer just then."

It took Celestia a moment to realise what she was talking about. And about five minutes to further realise that she wasn't kidding about it either. "What? Are you serious?"

"The Aisling Fearainn."

Celestia shook her head, still unsure as to just what it was Luna was proposing exactly. "What would entering the realm of dreams accomplish?"

"I understand that the power to enter dreams does not come naturally to you, but you've managed for a thousand years without me, and I believe that you are equal to this task," Luna said hurriedly, almost with a sense of hope – even enthusiasm – bubbling away under the surface. It was a slim chance, but if it meant a better outcome than last time, then she was prepared to see it through. "If you enter my mind while I am sleeping, you will find the personification of the Nightmare entity within it, and-"

"-And _what_?" asked Celestia incredulously. "We could have a pot of tea and a bit of a chat? _Oh, evil Nightmare Moon, would you mind awfully not possessing my sister and would you be so kind as to maybe relocate yourself to another dimension where we won't have to see or hear from you ever again_?"

"Well, yes," Luna said bluntly. "Maybe not that last part, though."

"Let me see if I've got this," Celestia said, blinking slowly, "you want me to try negotiating with something that simply wants power and glory for its own sake?"

"Is it really so different from conducting diplomatic talks with the griffons?" asked Luna, smiling slightly at her own feeble joke.

 _The griffons would not blot out the sky just because they could_.

Off Celestia's unconvinced look, Luna added, "Look, I agree, it's a long shot, but you wanted another option. If it doesn't work, at least you can send me back to the Moon secure in the knowledge that you did at least try everything this time."

 _Is that a rebuke_? _Or is it Nightmare Moon gaining a foothold_? Celestia knew that she should've been angry at her sister's statement, but she wasn't; regret had filled her heart every day for a thousand years, so it would take more than some hastily-chosen words to pierce her hide, but she also knew that there really had been no alternative. Nightmare Moon was far too powerful to be allowed to exist unchecked, much as it pained her to contemplate the destruction of a living – if parasitical – being. Reason and conflict had both failed, and a half-submerged castle in the Everfree Forest was testament to what could happen if Nightmare Moon was allowed out again. "I'm sorry," Celestia said simply.

"Don't be," Luna said, her muzzle shading to a more crimson hue. "I spoke out of turn and I apologise. Chalk it up to stress." Luna lifted her neck as much as she was able, while Celestia in turn lowered hers, until their horns were almost touching. Their auras flared to life, but they did not yet bring them together.

 _Few truly understand the significance of this gesture, but we do. When unicorn or alicorn horns touch, a small spark of magic is released; it flows from one to the other, becoming a part of them. In some cultures, it was used as a form of bonding in early foalhood. "More than a betrothal, less than a marriage," as the saying went. For others, it was a way of showing affection to a loved one. "Now, a part of me will be with you always." It is the first time that we've done this in over a thousand years and it might be the last. I want to savour the sweet taste of her magical essence, but there simply isn't time_.

"Are you ready?" Luna asked.

"No," replied Celestia truthfully.

With the slightest of smiles creasing her muzzle, Luna said, "I have no idea what you're going to find in there, but I know that you will overcome it nonetheless. I wish you success, dear sister."

 _Dear sister_ are the last two words that Celestia heard as it was at that point that Luna brought her horn into contact with her sister's; even though the touch is slight, a sharp _clack_ still echoes out. Soon, the suite and everything in it swam out of Celestia's focus.

The first emotion that Celestia registers upon waking up – although _falling asleep_ would be a more apt term, though the realm of dreams lies somewhere between the two states – is disappointment. Disappointed, but not surprised. Many things had drifted out of her mind in the intervening span of centuries, but she still remembered how much she hated school; unlike Twilight, lessons had bored her, and she'd hated having hours of her precious day consumed with pointless trivia and minutiae.

" _When I'm in charge of Equestria, I'll abolish school_ ," she'd once said after yet another miserable exam about ancient kings and their subjects. Of course, once she was elevated to the status of princess, she'd realised that education was actually important, and she'd set about trying to _improve_ it rather than dismantling it. Foals still complained about it, of course.

Celestia and Luna's education had consisted of rigorous schooling in various aspects of magic, in addition to the fundamentals, and none was more mysterious than that of the Aisling Fearainn: that strange dimension, inaccessible to all but a few, where dreams – literally – were made. It was often remarked that, in an infinite universe if something could exist then it must exist somewhere, and nowhere was that more true than here. Think it and you could do it.

If you were strong enough. It required _tremendous_ willpower not to become lost, not to give yourself over to the delights of this world and lose your identity amongst its many temptations. Ponies touched an aspect of it while they were asleep, just enough to for their subconscious minds to play upon their most secret fears, delights and fantasies for a few hours. If they were exposed to its full scope, they'd most likely lose their minds.

Luna's romantic, whimsical personality had been better suited to study of the dream realm than Celestia's more rational one, thus she was a natural choice to become the successor of their father as the Protector of Dreams. Things lurked in this dimension that, left unchecked, could so easily slip between the fragile borders between worlds. Let loose on Equestria, they would incite the sort of devastation not seen since the days of Discord and his acolytes.

 _And I thought I had it tough hurling a flaming ball of gas into the sky every morning_.

That feeling of disappointment stemmed from the fact that, as she had less control than Luna did over the environment around her, it merely looked like the suite that her _physical_ body was no doubt charmingly sprawled across while her mind took its flight of fancy. Somehow, she'd expected to see more of Luna in here, but she wasn't all that surprised: a lot of what happened in the dream world was based on your own preconceptions, and Celestia was more than a little worried by what was happening in this very room.

With Luna back, Celestia dearly hoped that this realm could once again be ruled effectively; she had done her best, but it was at best a pale imitation of her sister's natural gift.

In contrast to the room as it appeared in reality, here it was distinctly cold and unwelcoming, even though it showed no signs of Luna's, no, _Nightmare Moon_ 's violence; blue light – from the Moon, perhaps – illuminated the outer edges and many of the objects were familiar to Celestia, but they were also curiously muted. As if something had drained all of the life out of them. Of course, it could just be the fact that they're bad reproductions based on her memories. Still, the dull, grey paintings, pottery and assorted junk that had been collected or inherited over the years made her shiver.

The centre of the room was a nothingness, however; it wasn't just that the moonlight failed to reach it, it was as if the light was being sucked into some kind of black hole. An empty void. Celestia was careful to skirt the periphery at a safe distance. Whatever that black mass was, she did not want to be pulled inside. She guessed that it was something to do with Nightmare Moon. Perhaps the form that the parasite itself took in this dimension?

It made sense to her: something black and terrible sucking all of the life out of Luna's mind until it was replaced with its own darkness.

The core of the black mass began to roil; sticky, snake-like tendrils lashed out in every direction, as if searching for something that was causing it harm. Celestia retreated behind Luna's unmade bed to avoid being caught in the web it had created around the room. Doubtless, she was the source of its anxiety and it was doing its best to eliminate a potential threat to it. A filthy, oil-like substance clung to everything they touched and the smell when it hit Celestia's nostrils was sickening, and she had to force herself not to gag on the pungent odour.

Time passed and Celestia risked a look. The tendrils had retreated into one corner of the room, forming an inky blob; after a couple of moments, the blob began to take on a very familiar shape and it grew a couple of feet in stature. Celestia soon realised that she was looking at an onyx doppelgänger.

No, not quite a copy of herself.

A copy of her _sister_.

Just as she had done a couple of days earlier, Nightmare Moon stood before Princess Celestia in all of her glory; jet black pelt, ethereal mane the colour of starlight, and glistening, pointed fangs peeking out over a muzzle cut into a cruel smile. It was difficult not to picture those teeth biting down hard on one's flesh and drawing blood. Her head and wings were clad in a similar armour to that once worn by Equestrian soldiers when the world had been a far more dangerous and untamed place.

Celestia wondered if her subconscious impressions were making her appear more menacing than she had looked in reality, or was it something else at work? This _version_ of Nightmare Moon was not as powerful as the one that she had faced in reality, that Twilight and her friends had defeated with the Elements of Harmony, yet … there was something about her. Perhaps it was that simple imperative: when backed into a corner, a wounded animal was at its most dangerous, and there was something viciously _primal_ about that look in her beryl eyes.

Without warning, a beam of light coruscated from her horn and Celestia instinctively threw a barrier up to defend herself, but the blast had not been aimed at _her_ ; instead, it ripped the roof apart and exposed the room to the outside world. What there was of it.

Endless night.

This was, Celestia realised quickly, what Nightmare Moon had wanted all along: an Equestria bathed in perpetual moonlight. With the naked eye alone – and despite the competition it faced from the curtain of stars and the pearlescent glow of the never-waning Moon – she could make out the ruby-red swirl of the Horsehead Nebula. _A gift from the Goddess_ , her mother had once told her, _there to remind us that ponies are one of the most special creatures in all of the cosmos_. Its bloody countenance against the overriding blackness looked more like a warning than a present now.

"Princess Celestia," Nightmare Moon said, unfurling her wings to reveal the pointed spears attached to their tips, "is it not beautiful?"

Even if it was only a dream, it was difficult not to be transfixed by the vista; artists struggled for years to create that one image that would be remembered, whilst Luna could reshape her canvas at will and create a brand new masterpiece every night. "Yes, it is," Celestia eventually said, fighting to keep her tone neutral. "Luna had – _has_ – a natural talent for this that far surpasses my own."

"Indeed. Revising the cosmos every night, and what thanks did I, did we, ever get for it? Eternal, blissful ignorance."

"That's not true," Celestia said, shaking her head. It was useless arguing, she knew, but she also had to try. "Astronomers and astrologers for hundreds of years were inspired by what Luna did. Maybe she didn't get the appreciation that she deserved at the time, but in the present and future … things will be very different. Ponies will have a deeper understanding now of what the night has to offer, especially with Luna as its rightful protector."

Nightmare Moon favoured Celestia with a wicked smile. "I know why you're here, and I feel I ought to be upfront with you. It won't work. It's pointless for you to even try."

"Why is that?" asked Celestia blandly, wishing she didn't have to give this monstrosity her time.

Taking a few steps forward, her smirk growing wider, Nightmare Moon said, "She's so unimaginably broken, your little sister. Even if I hadn't been there to give her that little push over the edge, it was only a matter of time before she would have snapped her leash and turned against you. That jealousy and bitterness that I brought to the fore is in there, even now, and like me, it will only grow in strength. It is a wound that cannot be healed, cannot be treated, and can only be allowed to fester until it destroys her."

"That's not true," Celestia said hotly, her temper becoming almost as fiery as her words.

"Oh, whether you believe me or not is immaterial. The only thing stopping her from claiming all that she desires is you. Love – that most fleeting and ephemeral of all your petty emotions – for you keeps her restrained. But love does not last. Such a thing is not meant to in this world."

"Our bonds, love, friendship, kindness, hold us together and they are not so easily broken," replied Celestia. "I'm sorry, but you're wrong. This broken, weak pony that you are describing is yourself, not Luna." Celestia felt an awesome clarity filling her at that moment; all of the doubt and apprehension melted away, as if it were ice turning to water under the attentions of a warming Sun. The weight disappeared from her withers and she stood upright and proud. So many villains had tried and failed to conquer Equestria, but only one had ever succeeded in driving Celestia and Luna apart, and that would never be allowed to happen again.

"What do you mean?" asked Nightmare Moon, bristling at Celestia's tone. "Answer me!"

Celestia closed her eyes, a half-smile forming on her muzzle as she spoke. "Luna is the strongest of us all. Years ago, she made a mistake, but the past is past. She came back to seek forgiveness, to make up for what she had done, and the depth of her character can be seen in what she was willing to do here tonight: she was willing to risk death or another period of exile to be rid of you because _Equestria_ 's safety mattered more to her than her own." Tears rolled down her eyes and her throat became choked, but she continued to speak, "If it hadn't been for your whispering poison in her ear a thousand years ago, turning her against me, we would've faced you together. You would've been defeated without the need to banish her. You took my sister away from me _and I will never forgive you for that_!"

"Are you trying to convince me or yourself of that?" Nightmare Moon asked coldly. "What use do I have for your forgiveness, anyway? You cannot destroy me. You can damage me, seal me away, but I will always be there, so long as your sister lives."

Even before she had finished speaking, her horn was lighting up once more, flooded with the sort of power that only came from thousands of years of hatred and misery. Celestia barely had the time to dive out of the way of the howling blast of green lightning; it shattered an ornate column behind her, and a thousand pieces of smoking rubble hurled themselves in her direction until she was peppered with tiny cuts. Staggering painfully to her feet, Celestia fired back a volley of her own, but it was much, much too slow and Nightmare Moon easily deflected it with harmlessly into the sky with a shielding spell.

For just a moment, colour had returned to the world before it became a dark wilderness once more.

"If that's all you've got, Princess, then I suggest that you give up now," Nightmare Moon said, crowing triumphantly as she took to the sky, raining blasts down on Celestia who struggled to avoid them. "Don't forget, I have coexisted with your sister for more than a thousand years. Her power is mine to wield. I know the rules of this place better than you do. In here, I am the Goddess."

"No."

Nightmare Moon paused at the new, yet very familiar, voice echoing throughout the room. She looked around for the source of it, but it was nowhere to be seen. "Where are you?"

"Right here."

Celestia looked up from where she lay amid a pile of rubble, pain racking her body from the multitude of small wounds Nightmare Moon had indirectly caused; standing there was Luna, but she was not the quivering wreck she had been just moments ago. Her eyes were milky white, burning with an incandescent light. "You may have shared my mind, Nightmare Moon, but you do not own it. This is my world, and I reclaim it as is my right. No longer will I share a soul with you, monster."

Unthinkingly, Nightmare Moon charged, her horn ignited. "You are weak!"

"Sister, assist me."

"I can't," Celestia replied, only barely able to stand on all four hooves. "She's right. I don't understand this place like you do."

"We must combine our powers if we are to destroy her, Celestia," Luna said. "You _must_ assist me."

Celestia took her place alongside her sister, smiling slightly. _Even if this doesn't work, at least we got to work together one last time before the end_. Amazingly, she felt her strength returning; Luna was burning so hotly, almost white-hot now, pouring everything that she into one make-or-break attack. Celestia did likewise.

"Whatever happens," said Celestia to her sister, "I'm glad to have you back."

A radiant beam of energy erupted forth from the sisters; it was every colour at once, and the oncoming Nightmare Moon had nowhere to turn to as her whole being was engulfed and vaporised by the intense blast. She unleashed a jarring wail that filled the room – even over the din of Celestia and Luna's combined attack – and soon that, too, was gone.

Nightmare Moon was defeated.

Luna opened her eyes; in the centre of the room, a small sphere, about the size of an apple, floated in an ungainly fashion.

"Is that …?" Celestia began, not wanting to finish the question.

"Yes. Reduced to almost nothing by our assault. It will take years, perhaps centuries, for her to recover, if she ever does."

Celestia made a noise in the back of her throat.

"You think that we should kill her, sister?" The question was asked without malice. Without emotion of any kind, really.

"In the interests of Equestria's safety, I would rather not leave anything up to chance," said Celestia, though it disturbed her to even be _contemplating_ such an action against a now helpless foe. _A helpless foe who had done so much damage to both of us for a very, very long time_.

"Do you trust me?" Luna asked.

"Yes." Celestia wasn't sure what was more surprising: that she said it, or that she meant it. Yes, it had only been one day, but Luna had just so spectacularly proven herself worthy of her complete and utter confidence. "Yes, Luna, I trust you with my every fibre of my being."

With those words spoken, Luna smiled and tapped her horn against the quivering orb; for a moment, nothing happened, then it suddenly coiled itself around her horn, travelling along it, before making its way inside her head.

"Luna, what did you-?"

Celestia had no chance to finish her sentence before the room became scene to yet _another_ blinding white light; when it dissipated, Luna was left standing there.

Or at least, a pony that resembled Luna.

She had become subtly taller, her horn had lengthened, and she had gained Nightmare Moon's ethereal, starlight-hued mane. "Whatever else she was, you were right about one thing: Nightmare Moon was a lost, broken pony seeking something to make her complete. Perhaps a few centuries of living amongst us will provide that missing connection that she sought."

"Are you sure about this?" asked Celestia, not realising that she was holding her breath, expecting those demonic fangs to appear at any moment. "I mean, won't she-?"

"-She will have no power. She will be contained within a locked-off section of my mind with no way of spreading her poison to me. She will be … a passenger, nothing more. Able to witness, but not to act. She will feel rather like she's dreaming, actually."

Once again, Celestia was in awe of her sister; she had been ready to sacrifice herself, and now she was offering to be a halfway house for something that had caused her so much pain. There were no words, but she felt as though she ought to say _something_. "Luna-"

She was interrupted by her sister throwing her hooves around her. "Thank you."

"Uh, for what?" Celestia asked.

"For what you said earlier, sister," Luna said, tears in her eyes. "Ever since I came back, I've been afraid of what you must've thought of me. Whether you hated me, whether you _blamed_ me, for what had happened back then. Hearing what you said to Nightmare Moon gave me the strength I needed to finally accept the truth and defeat her." She looked embarrassed. "I should never have doubted you."

"Dear sister, many things in this world are subject to change, but not ever my feelings for you," Celestia replied, returning the embrace with both legs and wings. "In truth, it is I who should be apologising to you for ever having believed – even if it was only a momentary weakness – that you could be complicit in Nightmare Moon's destructive actions."

"Then," she favoured Celestia with a faint smile that made her look so childlike and innocent, "you truly do not fear me?"

"No, I do not. I am proud of you, Luna." Celestia was amazed at just how light she felt all of a sudden; Nightmare Moon had hoped to divide them, to weaken Luna to the point where she'd willingly accept her again, but she had failed due to underestimating the strength of their love for each other. Nothing would tear them apart again.

Finally extricating themselves from the hug, they spent a few moments in quiet contemplation; while the Nightmare entity had been contained – Celestia hoped for good this time, but she did not doubt Luna's ability to take action should she ever try to escape – there were other threats out there, and they had to be ready for them. She said as much out loud.

"It does not matter what is out there, dear sister," Luna said, placing a hoof on Celestia's shoulder. "Together, what could stand against us?"


End file.
